Added trove chapter to user guide

The user guide did not have a chapter on how to use trove.

This commit covers the first topic in the chapter,
how to create and access a database.

This commit is a partial implementation of the blueprint.

Change-Id: I3824ae796c0c1d4175ef9fe6edc8f1cbe8d300f8
blueprint: user-guide-trove-chapter
Merge "Added trove chapter to user guide"